Console keyboard freezes occasionally running MS-DOS 6.22

Running the latest distro of Proxmox 2.2
qemu/kvm VM
Keyboard freezes every time I "send key" <ctrl-alt-del>
If I open a second console for the same VM the keyboard un-freezes.

VM settings -
cores=1
cpu=qemu32
ide2=cdrom,media=cdrom
memory=64
net0=ne2k_pci,rate=100
nodename=proxmox
ostype=other
sata0=local:120/vm-120-disk-2.raw,size=8G
sockets=1
vga=cirrus